It has been known from German Pat. No. 1,229,753 to expose a test person for a short period of time to individual light spots in succession, appearing on the inner surface of a hemispherical shell. For this purpose, it is possible to arrange a plurality of light sources in the surface of the half shell, wherein these light sources are illuminated individually with the aid of an electronic control device. Alternatively, the individual light spots are projected into the half shell with the aid of a pivotable projector. The provision of several light spots simultaneously has not been contemplated in this reference.
In German Pat. No. 1,184,114 an apparatus is described wherein certain groupings of light spots are made to appear for a short period on a planar area which is not shielded laterally with respect to the person to be tested. The variation of different light spot groupings is therein accomplished by the mutual rotation of superimposed gratings which are correspondingly perforated. The light source is a flashtube arranged in a box behind the gratings. Due to the mechanical structure, it is practically impossible to control the eye to be tested with respect to its direction of fixation.
An arrangement is shown in U.S. Pat. No. 3,025,755 wherein the test person is subjected to light spots appearing in groups on a planar observation surface, which is not screened off laterally. For this purpose, the observation area is subdivided on its backside into varying fields wherein there are disposed respectively one or several incandescent lamps. These incandescent lamps are switched on in varying combinations.
Further, in German Pat. No. 1,202,024 a perimeter is described wherein the eye to be examined is subjected to various combinations of light spots for a short period of time; these light spots appear on a surface having the shape of a spherical segment. The light spots are illuminated by a common light source by way of a condenser lens. A rotatable perforated (Nipkow) disk in the light flux serves for selecting the light spot combinations. A selection of light spots, which can be made to appear in groups by rotating the perforated disk, is lit up with the aid of light conducting rods.